Overtime pay is part of your ex's net monthly resources on which child support will be calculated. You're going to have to show a good average over time. Private attorneys are better at handling these situations than the already overworked AG office. I think your ex is just trying to manipulate you. I bet it's not the first time.
I agree with the other attorney.
Net resources is clearly defined in the TX Family Code - which available to you for free on-line.
I have also addressed in other questions asked on this website & on my blog (www.txfamilylaw4u.blogspot.com) or go to my website (www.familylaw4u.com) and click to my blog. Also, if he is not visiting the child, that can be taked into account regarding setting child support since you have to feed the child more often.
I urge you to immediately retain an attorney because a private attorney will be more aggressive about going after child support than the TX A G office because they are overwhelmed and under-staffed. A private attorney can issue "discovery" on him to get additional information that the TX A G office does not have time to do. So get going - look on this excellent website for an attorney. Most accept payment plans. Good luck!
Overtime will be considered in calculating the "net resources" of the other party. I suggest finding an attorney in your area to handle this type of modification.
No attorney client-relationship is created by the above communication. You should always consider contacting an attorney with the details of your case in order to receive the most useful and accurate information.
His overtime does count when determining child support. The Texas Family Code Section 154.062 entitled Net Resources. You can find Section 154 at http://www.statutes.legis.state.tx.us/Docs/FA/htm/FA.154.htm. You will see under Section 154.062 (b)(1) that overtime counts. It appears that he is trying to manipulate you into to cancelling the child support review. You should hire your own attorney to advise you on the child support review process and to secure proof of his wages. This will ensure that child support will be appropriately set.